Needle-bar drive link for sewing machines



1954 R. E. JOHNSON NEEDLE-BAR DRIVE LINK FOR SEWING MACHINES Filed March 26, 1951 INVENTOB I (Well 0h again/1801a, BK

- ATTORNEY WI TNESS Patented Feb. 16, 1954 NES .Ralph E. Johnson, Mountainside, N. J., assignmto The Singer Manufacturing Company, Elizaboth, N. 3., a corporation of New Jersey Application March as, 1951, Serial 1%.217510 .2 Claims. (01. 112-421) invention relates to a needle-bar drive mechanism for a sewing machineand more pan-I ticularly. for a zigzag stitching type of sewing machine Q The invention has as a primary object to provide a needle-bar reciprocating link with con necting end pins which will not be loosened by vibration during operation of the sewing machine.

Another object of the invention is to provide a needle-bar reciprocating link with a shim serving as a locking means for the end connect ing pins of the link.

With the above and other objects in view, as will hereinafter. appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages at tained thereby will be readily understood by those skilled in the art. L

In the drawings,

Fig. 1 is an end elevation of a sewing machine head embodying the invention, the face plate being removed and the needle bar and gate partly broken away to expose the parts.

Fig. 2 is a vertical sectional view taken sub-v stantially on a line I-I of Fig. 1, with the needl bar shown in raised position. v

Fig. 3 is an exploded detail view of the improved needle bar reciprocating link.

Fig. 4 is an enlarged sectional view of the improved needle bar reciprocating link pivot pin, taken on the line 22 of Fig. l.

Referring more specifically to the drawings, the invention is disclosed as being embodied in a sewing machine having a frame including a head j I carried by-the usual bracket-arm l2, the head being closed at its outer end by the usual detachable face-plate I3. Rotatably journaled in a suitable bearing [4 provided in said bracket-arm I2 is a horizontally disposed actuating shaft !5, having one end extending from the head to' a driving power source (not shown). At its oppo site end, the actuating shaft I5 carries an actuating element or counterbalanced crank I5 provided with a crank-pin I! connected by a: link 18 with the-usual. take-up lever 19 suitably fulcrumed within the hollow head H. Pivotally journaled upon a pin 20 carried by an offset por-' tion of the crank-pin I1 is bifurcated journal sleeve 2| having depending and spaced ears ,22' between which the upper end of the improved needle-bar reciprocating link 23 and the 'shim 24 are pivotally mounted by a pin 25 for swinging movements about an axis transverse to the axis of the actuating shaft il5. The lower end of said link '23 is similarly pivoted on a pin 28 between upstanding spaced cars 21 of a bifurcated journal sleeve 28 pivoted upon a stud Hextendlng from a collar 30 suitably secured upon a verti' cally reciprocatory and laterally vibratory driven member or needle-bar 31.

The needle-bar 3.! carries at its lower end a needle 32 and is ioumaled for endwise reciprocation in suitable bearings provided upon a vibratory gate 33. The flattened upper end or the gate 33 is disposed within the bifurcated lower end of a supporting member 34 adjnstably threaded vertically into the upper wall of the bracket-arm head. The gate 33 is pivotally hung upon a screw s-tud 35 horizontally spanning the slot in the supporting member 34 to provide for swinging movements of the gate 33 about a pivotal axis substantially transverse to the axis of the actuating shaft l5. The lower end of the gate 33 is formed with opposed flat walls 36 slidably disposed between guide walls 31 of a guideway formed by vertically slotting the lower wall of the bracket arm head I l in a direction whereby the gate 33 is confined to swinging movements in a vertical plane. The needle bar 3! is restrained against turning in the gate bearings therefor, in a manner well known in the art, by a split guide-lug 38 on the collar 30, which guide-lug is slidably disposed in a vertical guideslot 39 provided in the gate 33. An arm 40 for laterally vibrating the gate 33 extends horizontally from the gate 33 and is connected to a suitable operating mechanism. Th mechanism for vibrating the arm 40 and gate 33 may be of any well known type such as that shown in the Patent No. 2,005,673, issued to G. M. Eames. I I

The improved needle-bar reciprocating link 23 is made, as shown in Fig. 3, so that the width of the link is slightly less than the width of the slot between the ears 22 and the ears 21. Holes 4| and 42 are drilled in the members 2| and 23, respectively, to receive the pin 25. Holes 43 and 44 are drilled in the members 28 and 23, respectively, to receive the pin 25. The link 23 is drilled and tapped intermediate its ends at 45 to receive a screw 45. The locking member or shim 24 is the same length and depth as th link 23 and of such a thickness as to function as a shim between the link 23 and the ears 22 and 21, respectively. Two slots 4'! and 4B are provided in one edge of the shim 24 near its ends and the pins 25 and 26 are formed with circumferential grooves 49 and 50 to receive the slotted portions 3 41 and 48, respectively, of the shim 24. The shim 24 is formed with a hole through which the screw 46 passes to enter the threaded hole 45 in the link 23 when the parts are in the assembled position.

From the foregoing description, it will be understood that the link 23 may be placed between the cars 22 and 21 and the pins 25 and 26 may then be inserted through the holes 4i, 42 and 43,

44, respectively, at opposite ends of the link until the left edge of the groove of each pin is alined with the right face of the link. The shim 24 may then be dropped between the right face of link 23 and the ears 22 and 21, so that the slotted portions 4'! and 48 of the link 24 engage in the grooves 49 and 50, respectively. The screw 46 may then be inserted through the hole 5| in the shim 24 and threaded into the hole 45 in the link 23. Since the slots 41 and 48 are in the same edge of the shim 24, the shim cannot rotate about the screw 46 and become disengaged from the grooves 49 and 50. As will lee-evident, the present construction provides a simple and easily assembled means of securely holding. the pins 25 and 25 in place while at the same time providing a means to shim the link 23 to the correct working clearances between the ears 22 and between the ears 21. This results in a smoother and quieter operation of the needle-bar and eliminates the possibility of machine failure due to loosened connecting link pivot-pins.

Having thus set forth the nature of the inventicn, what I claim herein is:

1. A sewing machine having a frame, an actuating crank, and a reciprocab-le and laterally vibratable driven member carried by said frame,

only one connecting link extending between said crank and said driven member, pivotal connections connecting said link to said crank and said driven member, each of said pivotal connections comprising a pivot pin having a peripherally grooved portion, a pivot pin locking shim extending parallel to said link and having slots in one edge entered by the grooved portion of said pins, and means securing said shim to said link.

2. In a sewing machine, a frame, a rotary actuating element carried by said frame, a crank-pin carried by said element, a reciprocatory and laterally vibratory needle-bar carried by said frame, a journal stud carried by said needle-bar, a bifurcated journal sleeve carried by said crankpin, a second bifurcated journal sleeve carried by said stud, a connecting link having its ends positioned in the bifurcated portions of said sleeves, pivot pins connecting said link to the bifurcated said journal sleeves, said shim having slots in one edge entered [by the grooved portions of said pivot-pins, and fastening means securing said shim to said link.

RALPH E. JOHNSON.

v References Cited in the file of this patent UNITED STATES PATENTS Name Date Landahl Dec. 11, 1928 Eames June 18,1935

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